<?php

namespace GFExcel\Field;

use GFExcel\Addon\GravityExportAddon;
use GFExcel\Values\BaseValue;

/**
 * A field transformer that serves as the base for every field that has subfields.
 * @since 1.6.0
 */
class SeparableField extends BaseField {
	/** @var string */
	public const SETTING_KEY = 'field_separation_enabled';

	/**
	 * @inheritdoc
	 * @return BaseValue[]
	 */
	public function getColumns() {
		if ( ! $this->isSeparationEnabled() ) {
			return parent::getColumns();
		}

		return $this->wrap( $this->getSeparatedColumns(), true );
	}

	/**
	 * @inheritdoc
	 * @return BaseValue[]
	 */
	public function getCells( $entry ) {
		$fields = gf_apply_filters( [
			'gfexcel_field_' . $this->field->get_input_type() . '_fields',
			$this->field->formId,
			$this->field->id,
		], $this->getSeparatedFields( $entry ), $entry );

		if ( $this->isSeparationEnabled() ) {
			$fields = array_map( function ( $value ) use ( $entry ) {
				return $this->filter_value( $value, $entry );
			}, $fields );

			return $this->wrap( $fields );
		}

		$value = $this->filter_value( implode( $this->getCombinedFieldsSeparator(), array_filter( $fields ) ), $entry );

		return $this->wrap( [ $value ] );
	}

	/**
	 * Returns the separator used to combine subfield values when separation is disabled.
	 *
	 * @since 2.5.0
	 *
	 * @return string The separator string.
	 */
	protected function getCombinedFieldsSeparator(): string {
		$glue = gf_apply_filters(
			[
				'gfexcel_field_separated_separator',
				$this->field->get_input_type(),
				$this->field->formId,
				$this->field->id,
			],
			"\n",
			$this->field
		);

		$glue = gf_apply_filters(
			[
				'gfexcel_field_' . $this->field->get_input_type() . '_separator',
				$this->field->formId,
				$this->field->id,
			],
			$glue,
			$this->field
		);

		return (string) $glue;
	}

	/**
	 * Get the separated fields to go along with the columns.
	 *
	 * @param mixed[] $entry The entry object.
	 *
	 * @return mixed[] The field values.
	 */
	protected function getSeparatedFields( $entry ) {
		$entry_keys = array_keys( $this->getSeparatedColumns() );

		return array_map( function ( $key ) use ( $entry ) {
			return $this->getFieldValue( $entry, $key );
		}, $entry_keys );
	}

	/**
	 * Whether we should use separated fields.
	 * @return bool Whether we should use separated fields.
	 */
	protected function isSeparationEnabled() {
		$plugin = GravityExportAddon::get_instance();

		return gf_apply_filters( [
			'gfexcel_field_separated',
			$this->field->get_input_type(),
			$this->field->formId,
			$this->field->id,
		], (bool) $plugin->get_plugin_setting( self::SETTING_KEY ), $this->field );
	}

	/**
	 * Get the column names for every active subfield.
	 * @return array
	 */
	protected function getSeparatedColumns() {
		return array_reduce( $this->getVisibleSubfields(), function ( $carry, $field ) {
			$field_id           = (string) $field['id'];
			$carry[ $field_id ] = gf_apply_filters( [
				'gfexcel_field_label',
				$this->field->get_input_type(),
				$this->field->formId,
				$this->field->id
			], $this->getSubLabel( $field ), $this->field );

			return $carry;
		}, [] );
	}

	/**
	 * Retrieve all active subfields for this field.
	 * @return array
	 */
	protected function getVisibleSubfields() {
		return array_filter( (array) $this->field->get_entry_inputs(), function ( $subfield ) {
			return ! isset( $subfield['isHidden'] ) || ! $subfield['isHidden'];
		} );
	}

	/**
	 * Get the label for a subfield.
	 *
	 * @param array|\ArrayAccess $field The field object.
	 *
	 * @return string The sub label.
	 */
	protected function getSubLabel( $field ) {
		if ( empty( trim( $field['customLabel'] ?? '' ) ) ) {
			return $field['label'];
		}

		return $field['customLabel'];
	}
}